Insufficient drainage infrastructure is compounding the situation, according to the Drainage and Irrigation Department.

Pahang is the worst hit, with almost 20,000 people evacuated to 73 relief centres in five districts as of 5pm yesterday. A spokesman of the state flood operations centre said Kuantan alone had more than 12,000 people at 46 relief centres.

Water and electricity supplies were cut off in most areas in Kuantan yesterday after several substations were hit by floods and roads in the city were inundated by up to 1m of water.

Minister in the Prime Minister's Department Datuk Seri Shahidan Kassim, who is in charge of the National Security Council, told the Dewan Rakyat that rescue operations went into full swing on Tuesday.

"A helicopter was dispatched to Kuantan to help in operations and I will be heading there myself later today (Wednesday)," he said.

Although rainfall is expected to lessen in the four states, the National Weather Forecast Centre of the Meteorological Department said yesterday it would take a few days for the flood waters to subside as the tide was now at its peak of about 4.5m high.

Its director Muhammad Helmi Abdullah added: "We do not expect the floods to get worse but they will take some time to subside - at least another two or three days."